There’s something very Shakespearean-sounding about "Mutability." Maybe it’s because here Wordsworth is dealing about an abstract concept, as Shakespeare often did in his sonnets, even when they were about love. Many of Wordsworth’s most well-known poems sound light and airy, but this one sounds heavy and dense, with lots of pauses and long words ("dissolution," "melancholy," "unimaginable"). And there’s hardly a noun without an adjective trailing along behind it: "tower sublime," "causal shout," "silent air." With all this dense language, we have the feeling of an older man reading aloud in a mahogany office full of books.
Another interesting feature of this poem is the repeated use of the same vowel sounds, especially i as in "time," and a as in "air" or "plain." These sounds occur both in the rhymes and in the middle of the lines. What’s more, Wordsworth chooses to continue using these sounds throughout the poem, even though the sonnet form would have allowed him to switch up his rhymes in the second half. We think that the alternation of different i and a or ai kind of suggests the "high" and "low" notes that the speaker mentions at the beginning of the poem.